Methods for calibrating a Nuclear-Medicine (N-M) imaging system including calibrating an N-M imaging system scanning unit for scanning detector uniformity map and energy resolution as well as generating an angular orientation map of a plurality of scanning units and a line source of radiation. There is further disclosed a jig for holding a line source during a calibration process of an N-M imaging system.

A method and apparatus are provided for positron emission imaging to calibrate energy measurements of a pixilated gamma-ray detector using energy calibration based on a calibration with a distribution energy signature (i.e., having more spectral features than just a single full-energy peak). The energy calibration can be performed using a deep learning (DL) network or a physics-based model. Using the DL network, a calibration spectrum is applied to either generate the measured-signal values of known energy values (e.g., spectral peaks for spectra of various radioactive isotopes) or the parameters of an energy-calibration function/model.

A system is disclosed for downhole logging. The system comprises a photon source configured to generate photons at different endpoint energies; at least one radiation detector configured to detect photons after interactions with a wellbore, a geological formation surrounding the wellbore, or both; an energy detection system configured to determine an endpoint energy of the photon source; and a processing system configured to determine properties of a wellbore, a geological formation, or both, based on photons detected at the at least one radiation detector and the endpoint energy determined by the energy detection system.

A charged particle detector array includes one or more pairs of super modules, one super module in a pair of super modules is positioned above a volume of interest (VOI), and the other super module in the pair of super modules is positioned below the VOI. This calibration technique first calibrates individual super modules in the one or more pairs of super modules while treating each super module being calibrated as a rigid body. Each super module in the one or more pairs of super modules further includes multiple vertically-stacked modules, and each module in the multiple vertically-stacked modules is composed of multiple layers of drift tubes. The calibration technique then calibrates individual modules in each of the super modules while treating each module being calibrated as a rigid body. Next, the calibration technique calibrates individual drift tubes in each layer of the modules.

The present invention relates to an X-ray detector comprising a directly converting semiconductor layer (60) having a plurality of pixels for converting incident radiation into electrical measurement signals with a band gap energy characteristic of the semiconductor layer, wherein said incident radiation is x-ray radiation emitted by an x-ray source (2) or light emitted by at least one light source (30, 33). Further, an evaluation unit (67) is provided for calculating evaluation signals per pixel or group of pixels from first electrical measurement signals generated per pixel or group of pixels when light from said at least one light source at a first intensity is coupled into the semiconductor layer and second electrical measurement signals generated per pixel or group of pixels when light from said at least one light source at a second intensity is coupled into the semiconductor layer, wherein said evaluation unit is configured to detect per pixel or group of pixels a noise peak in said first and second electrical measurement signals and to determine offset and gain per pixel or group of pixels from the detected noise peaks. A detection unit (69) is provided for determining detection signals from electrical measurement signals generated when x-ray radiation is incident onto the semiconductor layer, and a calibration unit (68) is provided for calibrating the detection unit on the basis of the evaluation signals.

Time of flight (TOF) corrections for radiation detector elements of a TOF positron emission tomography (TOF PET) scanner are generated by solving an over-determined set of equations defined by calibration data acquired by the TOF PET scanner from a point source located at an isocenter of the TOF PET scanner, suitably represented as matrix equation Formula I=CS where Formula I represents TOF time differences, C is a relational matrix encoding the radiation detector elements, and S represents the TOF corrections. A pseudo-inverse C.sup.−1 of relational matrix C may be computed to solve S=C.sup.−1 Formula I. TOF corrections can be generated for a particular type of detector unit by identifying the radiation detector elements in C by detector unit. Further, multi-photon triggering time stamps can be adjusted to first-photon triggering based on Formula II where P1 is average photon count using first-photon triggering and Pm is a photon count using multi-photon triggering.

Systems, methods, and apparatuses are provided for evaluating an image quality of an image produced by an x-ray computed tomography (CT) system.

There is provided a method and corresponding system and apparatus for image reconstruction based on image data from a photon-counting multi-bin x-ray detector. The method includes determining (S1) parameter(s) of a given functional form of the relationship between comparator settings expressed in voltage in the read-out chain of the x-ray detector and the corresponding energy threshold values expressed in energy based on a fitting procedure between a first set of data representative of a measured pulse height spectrum and a second set of data representative of a reference pulse height spectrum. The method also includes performing (S2) image reconstruction based on the image data and the determined parameter(s). In this way, efficient high-quality image reconstruction can be achieved.

A gamma-ray spectrometer calibration system comprises a light guide, a photomultiplier tube, a laser, and analysis electronics. The light guide is optically coupled to the scintillation crystal, the laser and the photomultiplier tube, such that the laser can provide reference signals to the photomultiplier tube. In some embodiments, one or more temperature sensors are provided, such that the analysis electronics determine initial settings and adjust the initial settings based on the temperatures measured by the temperature sensors. Additional apparatus, methods, and systems are disclosed.

A method (2) of producing a radiometric physical phantom of a biological organism to be irradiated or already irradiated having at least two volumes of appreciably different biological tissues comprises a step (6) of determining a radiological three-dimensional model on the basis of anatomical three-dimensional image(s) of the organism, a step (10) of producing a material framework of the phantom with the aid of a 3D printer, and a step (16) of filling the enclosures of the framework with gels. The radiological three-dimensional model groups together into radiological organs the mutually adjacent tissues having chemical compositions and densities which are similar. Each radiological organ is characterized geometrically by a radiological volume as sum of the volumes of the grouped tissues, and radiologically by a radiological class identifying the span of the chemical compositions and densities which are similar of the grouped tissues. A physical phantom manufactured by the method of production and a system for implementing the method of production. A method of experimentally determining the distribution of the doses of radiation on the phantom produced and a system for implementing the method of experimental determination.